A top drive is used in oilfield operations to manipulate a wellbore string, such as a drill string or a casing or liner string, The top drive is typically supported in a rig, such as a mast or derrick. The top drive provides torque to the wellbore string to drill a borehole. The top drive can move vertically up and down the rig via a pulley system or on rails, to string or remove pipes.
A top drive can include a backup wrench that can include a gripper device used to grip or position drill pipe during the drilling process. For example, an unattached drill pipe can be coupled by threads to a stump (i.e. an upper end of a string of drill pipe in the earth) by using the gripper to hold the unattached drill pipe in place while the top drive rotates the stump. The gripper of the top drive assembly can use a die block assembly actuated by a cylinder rod or piston to hold the drill pipe in place during the coupling process.
The die block of the gripper requires regular inspection, maintenance and replacement. However, current solutions for mechanically coupling the die block to the gripper can be unsafe, inefficient and can inadequately seal the die block structure from the elements experienced during the drilling process.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.